This typically happens when playing stronghold, which by the way is a horrible game type that players are forced to play when searching for player versus Ai. Once the enemy teleports my units outside of the map I can no longer use them or build more units since the units are not destroyed. This cuts by population in half or more. Essentially it gives the computer and ability to permanently take you out of the game with one leader Power. The units that are teleported out of the map are not visible but when you hit down on the directional pad it will bring the camera to the ghost units. This needs to be fixed along with strongholds being taken out of this playlist.